What was found
WING GEAR EXTENSION FAILED TO EXTEND. PERFORMED INSP LANDING W/ ONE MAIN GEAR UP PHASE I INSP ON RT & LT SIDE. PER MM 5-51-40 NO FINDINGS. REPLACED NR 4 HYD RETURN FILTER PER MM 29-11-29, REPLACED NR 4 HYD CASE DRAIN FILTER PER MM 29-11-18, REPLACED NR 4 HYD RETURN FILTER MODULE PER MM 29-11-29 OPS & LEAK CHECK GOOD. PERFORMED INSP'S PER MM 5-51-39, 5-51-05 NO FINDINGS, PHASE I COMPLIED W INSP PER BOEING MSG EV12-ERV-12-0089-01C NO DEFECTS NOTED. R&R NR 4 EDP PER 747 MM 29-11-05 OPS & LEAK CHECK GOOD, DMI CLEARED, PLACARD REMOVED. REPLACE NR 4 ADP PER MM 29-11-17 OPS & LEAK CK GOOD. PERFORMED ALT EXTENSION OF WING GEAR PER B747 MM 32-36-00, NO DEFECTS NOTED GEAR FREE FALLED SMOOTH.